Retrospective cohort study of 215 patients after posterior lumbar arthrodesis. Used Kaplan-Meier survivorship analysis to quantify the rate of symptomatic adjacent segment disease requiring reoperation at 5 and 10 years. Also assessed whether patient demographics, instrumentation, fusion length, or preoperative disc grade predict that risk.
When consenting a patient for posterior lumbar fusion, you have specific numbers to give: roughly 1 in 6 will need adjacent-level surgery within 5 years, and more than 1 in 3 by 10 years.
Those odds hold regardless of what the preoperative MRI shows at the adjacent level, whether you use instrumentation, and whether you are doing a single- or multi-level construct. No imaging or surgical variable identifies the high-risk patient.
The counterintuitive finding here — that single-level fusion carries 3.4× higher risk than multi-level fusion. Is a common board trap. It does not mean short fusions are more dangerous per segment. It means a patient fused at one level has four segments left at risk, while a patient fused from thoracic spine to L5 has one.
L4-L5 is the highest-risk adjacent level (21.8% prevalence). L5-S1 is paradoxically low-risk (7.2%). Worth knowing when counseling patients about an L4-L5 index fusion specifically.
Retrospective cohort study of 215 patients after posterior lumbar arthrodesis. Used Kaplan-Meier survivorship analysis to quantify the rate of symptomatic adjacent segment disease requiring reoperation at 5 and 10 years. Also assessed whether patient demographics, instrumentation, fusion length, or preoperative disc grade predict that risk.
When consenting a patient for posterior lumbar fusion, you have specific numbers to give: roughly 1 in 6 will need adjacent-level surgery within 5 years, and more than 1 in 3 by 10 years.
Those odds hold regardless of what the preoperative MRI shows at the adjacent level, whether you use instrumentation, and whether you are doing a single- or multi-level construct. No imaging or surgical variable identifies the high-risk patient.
The counterintuitive finding here — that single-level fusion carries 3.4× higher risk than multi-level fusion. Is a common board trap. It does not mean short fusions are more dangerous per segment. It means a patient fused at one level has four segments left at risk, while a patient fused from thoracic spine to L5 has one.
L4-L5 is the highest-risk adjacent level (21.8% prevalence). L5-S1 is paradoxically low-risk (7.2%). Worth knowing when counseling patients about an L4-L5 index fusion specifically.